CN107984978B

CN107984978B - Tyre for vehicle wheels

Info

Publication number: CN107984978B
Application number: CN201710531830.0A
Authority: CN
Inventors: 长泽宏器
Original assignee: Sumitomo Rubber Industries Ltd
Current assignee: Sumitomo Rubber Industries Ltd
Priority date: 2016-10-26
Filing date: 2017-06-28
Publication date: 2021-11-02
Anticipated expiration: 2037-06-28
Also published as: EP3315326A1; US20180111421A1; EP3315326B1; JP6790722B2; JP2018069859A; CN107984978A

Abstract

The present invention provides a tire capable of exhibiting excellent on-snow performance. The tire has a tread portion (2). The tread portion (2) has a first tread portion (2A) between the tire equator (C) and a first tread end (Te 1). The first tread portion (2A) is provided with: the tire comprises a shoulder main groove (5) extending continuously and linearly in the tire circumferential direction, a plurality of inclined main grooves (10) extending obliquely from a first tread end (Te1) toward the tire equator (C) side and traversing the shoulder main groove (5), and a plurality of inclined land portions (20) divided between the adjacent inclined main grooves (10) in the tire circumferential direction. Each sloping land portion (20) is provided with: an outer inclined auxiliary groove (13) extending from the inclined main groove (10) and interrupting the inclined land portion (20) on the inner side of the tire shoulder main groove (5) in the tire axial direction, and an inner inclined auxiliary groove (14) completely traversing the inclined land portion (20) on the inner side of the outer inclined auxiliary groove (13) in the tire axial direction.

Description

Tyre for vehicle wheels

Technical Field

The present invention relates to a tire capable of exhibiting excellent on-snow performance.

Background

For example, patent document 1 listed below proposes a winter tire provided with a main groove extending linearly continuously in the tire circumferential direction and a plurality of inclined main grooves traversing the main groove.

However, the tire of patent document 1 has room for further improvement in improving the on-snow performance.

Patent document 1: japanese laid-open patent publication No. 2013-136333

Disclosure of Invention

The present invention has been made in view of the above problems, and a main object thereof is to provide a tire that can exhibit excellent on-snow performance.

The tire of the present invention has a tread portion, wherein the tread portion has a first tread portion between a tire equator and a first tread end, and the first tread portion is provided with: a shoulder main groove continuously extending in a straight line in the tire circumferential direction on the first tread end side; a plurality of inclined main grooves extending obliquely from the first tread end toward the tire equatorial side and crossing the shoulder main grooves; and a plurality of inclined land portions defined between the inclined main grooves adjacent to each other in the tire circumferential direction, each of the inclined land portions being provided with: an outer oblique auxiliary groove extending from the oblique main groove and interrupted in the oblique land portion, on a tire axial direction inner side of the shoulder main groove; and an inner oblique sub-groove that is completely transverse to the oblique land portion, inside in the tire axial direction of the outer oblique sub-groove.

In the tire according to the present invention, it is preferable that the outer oblique sub-groove and the inner oblique sub-groove are respectively inclined in opposite directions to the main oblique groove.

In the tire of the present invention, it is preferable that the inner oblique sub-groove has a larger groove width than the outer oblique sub-groove.

In the tire of the present invention, it is preferable that the inner oblique sub-groove extends so as to be smoothly continuous with the outer oblique sub-groove provided in the oblique land portion adjacent in the tire circumferential direction via the oblique main groove.

In the tire of the present invention, it is preferable that the inclined main groove has a groove width larger than that of the shoulder main groove at least in a region outside the shoulder main groove in the tire axial direction.

In the tire of the present invention, it is preferable that the distance in the tire axial direction from the tire equator to the groove center line of the shoulder main groove is 0.25 to 0.35 times the tread width.

In the tire of the present invention, it is preferable that an angle between the shoulder main groove and the oblique main groove is 30 ° to 60 °.

The first tread portion of the tire of the present invention is provided with: the tire has a shoulder main groove extending linearly continuously in the tire circumferential direction on the first tread end side, a plurality of inclined main grooves extending obliquely from the first tread end toward the tire equatorial side and crossing the shoulder main groove, and a plurality of inclined land portions partitioned between adjacent inclined main grooves in the tire circumferential direction.

When the tire runs on snow, the tire shoulder main groove can form a long snow column extending along the tire circumferential direction, and further can obtain a large snow column shearing force in the tire axial direction. When running on snow, the inclined main grooves form long snow columns extending obliquely with respect to the tire axial direction and shear the snow columns, thereby obtaining a large traction force.

Each inclined land portion of the tire of the present invention is provided with: an outer oblique auxiliary groove extending from the oblique main groove and interrupting in the oblique land portion on the inner side in the tire axial direction of the shoulder main groove, and an inner oblique auxiliary groove completely traversing the oblique land portion on the inner side in the tire axial direction of the outer oblique auxiliary groove.

In general, when traveling on snow, the snow entering the inclined main trench tends to be compacted while moving toward the respective sub trenches. The inclined auxiliary ditches of the present invention can further improve the performance on snow by compacting and shearing the snow entering from the inclined main ditches. In particular, in the present invention, the outer oblique auxiliary trench is interrupted in the oblique land portion, so that the snow moved from the oblique main trench side can be further strongly compacted during travel on snow, and a large snow column shearing force can be obtained.

Further, since the inner oblique sub-groove completely traversing the oblique land portion is provided inside the outer oblique sub-groove, the land portion piece provided with the outer oblique sub-groove is surrounded by the shoulder main groove, the oblique main groove, and the inner oblique sub-groove. Therefore, when the vehicle travels on snow, the land portion pieces can be appropriately deformed, and the snow in the outer inclined sub-groove can be suppressed from being clogged.

As described above, the tire of the present invention can exhibit excellent on-snow performance.

Drawings

Fig. 1 is a development view of a tread portion of a tire according to an embodiment of the present invention.

Fig. 2 is an enlarged view of the first tread portion of fig. 1.

Fig. 3 is a partially enlarged view of the inclined land portion of fig. 2.

Fig. 4 is a developed view of a tread portion of the tire of comparative example 1.

Fig. 5 is a developed view of a tread portion of the tire of comparative example 2.

Description of reference numerals: 2 … tread portion; 2a … first tread portion; 5 … shoulder main groove; 10 … inclined main channel; 13 … outer side inclined minor groove; 14 … inner side inclined minor groove; 20 … sloping land portions; c … tire equator; te1 … first tread end.

Detailed Description

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a developed view of a tread portion 2 of a tire 1 of the present embodiment. The tire 1 of the present embodiment is suitably used as a winter tire for a passenger vehicle, for example. The tire 1 of the present embodiment has a directional pattern in which the rotation direction R is specified. The rotation direction R is indicated by characters or symbols on the side wall portion (not shown), for example.

As shown in fig. 1, a tread portion 2 of a tire 1 of the present embodiment includes: a first tread portion 2A between the tire equator C and the first tread end Te1, and a second tread portion 2B between the tire equator C and the second tread end Te.

The first tread end Te1 and the second tread end Te2 are contact positions at the outermost side in the axial direction of the tire when a normal load is applied to the tire 1 in a normal state and contact is made at a 0 ° camber angle as a plane. The normal state is a state in which the tire rim is assembled to the normal rim and the normal internal pressure is applied thereto, and no load is applied. In the present specification, unless otherwise specified, the dimensions and the like of each portion of the tire are measured in a normal state.

The "regular Rim" is a Rim that defines a specification for each tire in a specification system including the specification that the tire conforms to, and is, for example, "standard Rim" in the case of JATMA, "Design Rim" in the case of TRA, and "Measuring Rim" in the case of ETRTO.

The "normal internal PRESSURE" is a PRESSURE of air specified for each TIRE in a specification system including a specification which the TIRE conforms to, and is "maximum air PRESSURE" in the case of JATMA, a maximum value described in a table "TIRE LOAD conditions AT TIREs cool stability requirements" in the case of TRA, and "stability requirements" in the case of ETRTO.

The "normal LOAD" is a LOAD specified for each TIRE in a specification system including specifications to be followed by the TIRE, and is "maximum LOAD CAPACITY" in the case of JATMA, a maximum value described in a table "TIRE LOAD conditions AT TIREs COLD stability requirements" in the case of TRA, and a "LOAD CAPACITY" in the case of ETRTO.

The first tread portion 2A and the second tread portion 2B are provided with: the tire shoulder main groove 5, a plurality of inclined main grooves 10, and inclined land portions 20 defined between adjacent inclined main grooves 10 in the tire circumferential direction. The first tread portion 2A and the second tread portion 2B have substantially the same configuration. Hereinafter, the configurations of the shoulder main groove 5, the inclined main groove 10, and the inclined land portion 20 provided in the first tread portion 2A will be described, and the respective configurations provided in the second tread portion 2B will not be described.

Fig. 2 shows an enlarged view of the first tread portion 2A. As shown in fig. 2, the shoulder main groove 5 continuously and linearly extends in the tire circumferential direction on the first tread end Te1 side.

In the present embodiment, the distance L1 from the tire equator C to the groove center line of the shoulder main groove 5 is preferably 0.25 to 0.35 times the tread width TW (see fig. 1, the same applies hereinafter). The tread width TW is the distance in the tire axial direction between the first tread end Te1 and the second tread end Te2 in the normal state described above.

The groove width W1 of the shoulder main groove 5 is preferably 1.5% to 4.5% of the tread width TW, for example.

During snow travel, the shoulder main groove 5 can form a long snow column extending in the tire circumferential direction, and a large snow column shearing force can be obtained in the tire axial direction.

The oblique main groove 10 extends obliquely from the first tread end Te1 toward the tire equator C side and traverses the shoulder main groove 5. The tilted main groove 10 of the present embodiment extends, for example, to a position beyond the tire equator C. During travel on snow, the inclined main grooves 10 form long snow columns extending obliquely with respect to the tire axial direction, shear the snow columns, and can obtain a large traction force.

The tilted main channel 10 of the present embodiment includes, for example, a main body 11 and an inner portion 12. The main body portion 11 extends, for example, from the first tread end Te1 at least to a region between the shoulder main groove 5 and the tire equator C, and in the present embodiment, extends to the front of the tire equator C. The inner portion 12 is connected to the tire equator C side of the main body 11, for example, and traverses the tire equator C.

The main body portion 11 extends, for example, while gradually decreasing the angle θ 1 with respect to the tire circumferential direction from the first tread end Te1 toward the tire equator C side. The angle θ 1 of the main body 11 is preferably 15 to 75 °, for example. Such a body portion 11 exerts snow column shearing force also in the tire axial direction, and contributes to improvement of cornering performance on snow.

The angle θ 2 between the shoulder main groove 5 and the main body portion 11 of the inclined main groove 10 is preferably 30 ° or more, more preferably 40 ° or more, and preferably 60 ° or less, more preferably 50 ° or less. Such a body portion 11 can exhibit the above-described effects without impairing the drainage performance of the shoulder main groove 5 during wet running.

The body portion 11 preferably has a groove width W2 gradually decreasing toward the tire axial direction inner side, for example. The groove width W2 of the body 11 is preferably 2% to 7% of the tread width TW, for example. Such a main body portion 11 contributes to maintaining steering stability on a dry road surface and improving on-snow performance and wet performance.

In order to further improve the on-snow performance and the wet performance, the main body portion 11 preferably has a groove width larger than the shoulder main groove 5 at least in a region outside the shoulder main groove 5 in the tire axial direction.

The inner portion 12 communicates with the body 11 on a rear landing side in the rotation direction R (hereinafter, may be simply referred to as "rear landing side") with respect to the end of the body 11. In other words, the inner portion 12 branches from the main body portion 11 and extends toward the tire equator C.

The inner portion 12 extends linearly, for example, while being inclined in the same direction as the main body portion 11. The inner portion 12 extends across, for example, the tire equator C and is connected to the inclined main groove 10B provided in the second tread portion 2B. Since a large ground contact pressure tends to act in the vicinity of the tire equator C during tire running in general, the inner side portion 12 can strongly compress snow, and can exhibit excellent on-snow traction.

In order to exert the snow column shearing force also in the tire axial direction, the angle θ 3 of the inner side portion 12 with respect to the tire axial direction is preferably 10 to 30 °, for example.

Each inclined land portion 20 is provided with: an outer oblique sub groove 13 extending from the oblique main groove 10 inward of the shoulder main groove 5 in the tire axial direction and interrupted in the oblique land portion 20; and an inner oblique sub-groove 14 completely traversing the oblique land portion 20 on the outer side of the outer oblique sub-groove 13 in the tire axial direction.

In general, when traveling on snow, the snow entering the inclined main trench 10 tends to be compacted while moving toward the respective sub trenches. The inclined sub-grooves 13 and 14 of the present invention can further improve the on-snow performance by compacting and shearing the snow entering from the inclined main groove 10. In particular, in the present invention, since the outer oblique auxiliary trench 13 is interrupted in the oblique land portion 20, the snow moving from the oblique main trench 10 side can be further strongly compacted during travel on snow, and a large snow column shearing force can be obtained.

Further, since the inner oblique sub-groove 14 completely traversing the oblique land portion 20 is provided inside the outer oblique sub-groove 13, the land portion piece provided with the outer oblique sub-groove 13 is surrounded by the shoulder main groove 5, the oblique main groove 10, and the inner oblique sub-groove 14. Therefore, the land portion pieces can be appropriately deformed when the vehicle travels on snow, and the snow in the outer oblique sub-groove 13 can be prevented from being clogged.

The outer oblique sub-grooves 13 communicate with the rear-land-side oblique main grooves 10, for example, and are inclined toward the first-land side in the rotation direction R (hereinafter, may be simply referred to as "first-land side") and toward the first tread end Te 1. In other words, the outer oblique sub-groove 13 is inclined oppositely to the oblique main groove 10. Preferably, the outer oblique minor groove 13 of the present embodiment is smoothly curved.

The angle θ 4 of the outer oblique minor groove 13 with respect to the oblique major groove 10 is preferably 70 ° or more, more preferably 75 ° or more, and preferably 90 ° or less, more preferably 85 ° or less. This can suppress uneven wear of the land portion pieces provided with the outer oblique sub-grooves 13, and improve on-snow performance.

In order to suppress uneven wear of the inclined land portion 20 and improve on-snow performance, the distance L2 in the tire axial direction from the intersection 15 of the extension line of the groove center line of the outer oblique sub-groove 13 and the groove center line of the oblique main groove 10 to the tire equator C is preferably 0.15 to 0.25 times the tread width TW, for example.

The groove width W3 of the outer oblique minor groove 13 is preferably gradually reduced toward the end portion interrupted in the oblique land portion 20, for example. As a result, the snow in the outer oblique auxiliary grooves 13 is easily discharged along with the deformation of the oblique land portion 20 during travel on snow. The groove width W3 of the outer oblique sub-groove 13 is preferably 1% to 3% of the tread width TW, for example.

The inner oblique sub-grooves 14 are preferably inclined toward the tire equator C from the oblique main grooves 10 on the first landing side toward the oblique main grooves 10 on the second landing side, for example. In other words, the inner oblique sub-grooves 14 are inclined in the opposite direction to the oblique main grooves 10 and in the same direction as the outer oblique sub-grooves 13.

The angle θ 5 of the inner oblique minor groove 14 with respect to the oblique major groove 10 is preferably 70 ° or more, more preferably 75 ° or more, and is preferably 90 ° or less, more preferably 85 ° or less. Such inner oblique auxiliary grooves 14 can suppress uneven wear of the oblique land portion 20, generate snow columns extending in a direction different from that of the oblique main grooves 10, and improve turning performance on snow.

The distance L3 from the intersection 18 of the groove center line of the inner oblique sub-groove 14 and the groove center line of the oblique main groove 10 provided on the rear landing side thereof to the tire equator C in the tire axial direction is preferably 0.05 to 0.15 times the tread width TW, for example. Thereby suppressing uneven wear of the sloping land portion 20 and improving on-snow performance.

As a more preferable aspect, the inner oblique sub-groove 14 of the present embodiment extends so as to be smoothly continuous with the outer oblique sub-groove 13 of the oblique land portion 20 provided adjacent in the tire circumferential direction via the oblique main groove 10. Thus, the outer oblique sub-grooves 13 and the inner oblique sub-grooves 14 are integrated to form a large snow column, thereby exhibiting excellent on-snow performance. Further, "smoothly continue through the tilted main groove 10" means that a region in which one of the sub grooves extends along its shape overlaps with the opening portion of the other sub groove on the tilted main groove 10 side.

The groove width W4 of the inner oblique sub-groove 14 of the present embodiment is preferably 1% to 3% of the tread width TW, for example. Thereby suppressing snow clogging in the inner oblique auxiliary groove 14.

Fig. 3 shows an enlarged view of the sloping land portion 20. As shown in fig. 3, the inclined land portion 20 is divided by the shoulder main groove 5 and the inner inclined sub-groove 14: crown blocks 21, intermediate blocks 22 and shoulder blocks 23.

The crown blocks 21 are provided, for example, on the tire axial direction inner side of the inner oblique sub groove 14 and across the tire equator C.

The crown block 21 of the present embodiment preferably has a front end 25 protruding toward the ground-contacting side in the rotation direction R, for example. The tip end portion 25 of the present embodiment preferably has a V-shaped edge protruding toward the ground contacting side. Such a tip end portion 25 can generate a large reaction force when traveling on ice, for example.

The crown block 21 is preferably provided with a plurality of crown sipes 26 extending in the tire axial direction. Such crown sipes 26 can provide greater traction when driving on ice.

The middle block 22 is disposed between the inner inclined sub groove 14 and the shoulder main groove 5. The intermediate block 22 is formed substantially rectangular, for example, except for the point where the outer oblique sub-groove 13 is provided. The intermediate block 22 of the present embodiment is formed to be laterally long, for example, along the longitudinal direction of the tilted main groove 10. Such intermediate blocks 22 are appropriately deformed in the tire circumferential direction during snow running, thereby contributing to discharge of snow in the tilted main grooves 10.

The intermediate block 22 is preferably provided with a plurality of intermediate sipes 27 inclined in the opposite direction to the inclined main groove 10, for example. Such a middle sipe 27 can exert frictional force in a plurality of directions when running on ice.

The shoulder blocks 23 are disposed between the shoulder main groove 5 and the first tread end Te 1. The shoulder blocks 23 are formed in a horizontally long rectangular shape along the longitudinal direction of the inclined main groove 10, for example.

The shoulder block 23 is preferably provided with a plurality of shoulder sipes 28 inclined in the same direction as the inclined main groove 10, for example. Such a shoulder sipe 28 can reduce the rigidity of the shoulder block 23 and exhibit excellent anti-rolling performance.

While the tire according to the embodiment of the present invention has been described in detail, the present invention is not limited to the above specific embodiment, and can be implemented by being modified into various embodiments.

Examples

Based on the specifications of table 1, a tire having a size 255/55R18 of the basic tread pattern of fig. 1 was prototyped. As comparative example 1, a tire was produced by trial without the outer oblique sub-grooves and the inner oblique sub-grooves, as shown in fig. 4. As comparative example 2, as shown in fig. 5, a tire provided with inner oblique sub-grooves and not provided with outer oblique sub-grooves was prototyped. The on-snow performance, wet performance and wear resistance of each test tire were tested. The common specification and test method of each test tire are as follows.

Mounting a rim: 18X 8.0J

Air pressure: 230kPa for the front wheel and 250kPa for the rear wheel

Testing the vehicle: exhaust volume 3000cc, four-wheel drive car

< Performance on snow >

The distance when the test vehicle was accelerated from 5km/h to 20km/h on snow was measured by a GPS, and the average acceleration was calculated. The result is an index indicating that the average acceleration of comparative example 1 is 100, and the larger the value, the more excellent the on-snow performance.

< Wet road Performance >

The test vehicle was run on an asphalt road surface of 100m radius provided with a puddle having a depth of 10mm and a length of 20m, and the lateral acceleration (lateral G) of the front wheel was measured. As a result, the average lateral G of the speed of 55 to 80km/h is expressed as an index with the value of comparative example 1 being 100. The larger the value, the more excellent the wet performance.

< wear resistance >

The amount of wear of the inclined land portion when the test vehicle was driven on the asphalt road surface for a certain distance was measured. The result is an index with comparative example 1 being 100, and a smaller value indicates more excellent wear resistance.

The results of the test are shown in table 1.

TABLE 1

The results of the test can confirm that: the tires of the examples improve on-snow performance as well as wet performance. In addition, it was confirmed that the tire of the example maintained the wear resistance.

Claims

1. A tire having a tread portion, characterized in that,

the tread portion has a first tread portion between a tire equator and a first tread end,

the first tread portion is provided with:

a shoulder main groove continuously extending in a straight line in the tire circumferential direction on the first tread end side;

a plurality of inclined main grooves extending obliquely from the first tread end toward the tire equatorial side and crossing the shoulder main grooves; and

a plurality of inclined land portions divided between the inclined main grooves adjacent in the tire circumferential direction,

each of the inclined land portions is provided with:

an outer oblique auxiliary groove extending from the oblique main groove and interrupted in the oblique land portion, on a tire axial direction inner side of the shoulder main groove; and

an inner oblique sub-groove completely traversing the oblique land portion on an inner side in a tire axial direction of the outer oblique sub-groove,

the angle between the tire shoulder main groove and the inclined main groove is 30-60 degrees.

2. The tire according to claim 1,

the outer inclined minor groove and the inner inclined minor groove are inclined oppositely to the inclined main groove, respectively.

3. Tire according to claim 1 or 2,

the inner oblique minor groove has a larger groove width than the outer oblique minor groove.

4. Tire according to claim 1 or 2,

the inner oblique sub-groove extends to be smoothly continuous with the outer oblique sub-groove provided in the oblique land portion adjacent in the tire circumferential direction via the oblique main groove.

5. Tire according to claim 1 or 2,

the inclined main groove has a groove width larger than that of the shoulder main groove at least in a region outside the shoulder main groove in the tire axial direction.

6. Tire according to claim 1 or 2,

the distance from the tire equator to the tire shoulder main groove central line in the tire axial direction is 0.25-0.35 times of the tread width.